EAS 210 - Lecture Notes Flashcards
Layers of the earth
Inner core (solid iron)
Outer core (liquid iron)
Mantle (silicate mineral with Fe, Mg)
Crust (silicate mineral with Na, Ca, Al)
Lithosphere
Asthenosphere
Which layer of the earth is made up of tectonic plates?
Lithosphere
Describe Minerals(5)
- Naturally occurring
- solid at surface pressure and temperature
- regular internal structure of atoms (crystalline)
- narrowly defined chemical composition
- Usually inorganic
Luster
The quality and intensity of light reflected from a mineral
Mohs Scale (1-10)
10 - Diamond
9 - Corundum
8 - Topaz
7 - Quartz
6 - Potassium Feldspar
5 - apatite
4 - Fluorite
3 - Calcite
2 - Gypsum
1 - Talc
What is fracture? What are the different kinds of fracture?
Fracture refers to the irregular breakage of a mineral
Irregular
Splintery
Conchoidal (curved surface)
How are igneous rocks formed?
Molten rock (magma or lava) solidifies
Magma vs. Lava
Magma is molten rock beneath the surface of the Earth
Once magma reaches the surface, it is called lava
Intrusive vs. Extrusive
Intrusive cools slowly underground
Extrusive reaches the surface and cools quickly
Felsic vs. Mafic
Felsic - high silica, lower melting point, high viscosity
Mafic - low silica, higher melting point, low viscosity
List the 4 common chemical compositions of igneous rocks. Additionally, list the rock pair and their silica percentages
Felsic: Granite/Rhyolite, more than 65% silica
Intermediate: Diorite/Andesite, 65-53% silica
Mafic: Gabbro/Basalt, 52-45% silica
Ultramafic: Peridotite/Komatiite, <45% silica
Magmatic Differentiation
As magma cools, mafic minerals are the first to crystallize (and sink to the bottom). This makes the composition of the remaining liquid more felsic
What does Bowen’s reaction series show?
The sequence in which minerals crystallize from magma
Viscosity relationships (silica and temperature)
Increasing silica increases viscosity
Increasing temperature decreases viscosity
Shield Volcano
Formed by mafic lavas with low viscosity
Very gentle slopes
Common in Hawaii
Cinder Cone
A.K.A Scoria Cone
Typically formed by one eruptive episode and considered a monogenetic volcano
Composite Volcano
A.K.A Strato-Volcano
Alternating layers of ash and lava
Steeper slopes than shield volcanoes because the lava is more viscous
Generally andesite-rhyolite
Symmetry implies young and active
Very unstable and liable to collapse with major landslides
Usually several millions years for a lifespan
Calderas
Form towards the end of the lifecycle of an arc volcano
Where are most volcanoes located?
On plate boundaries. Plate tectonics explain volcano types
Where are most volcanoes located?
On plate boundaries. Plate tectonics explain volcano types
Weathering
The physical and/or chemical breakdown of rock at or near the surface of the Earth to produce sediment
Mechanical Weathering and the 3 types
Breaks the rock into smaller pieces. Important because the increase in surface area allows chemical weathering to be more effective
Frost Wedging
Sheeting
Biological Activity
Chemical Weathering and the 3 types
Chemical reactions breakdown rock. End result is chemical sediment (Ions dissolved in water). Hot wand wet environments accelerate chemical weathering
Dissolution
Oxidation
Hydrolysis
Spheroidal Weathering
The concept that chemical weathering is faster on corners and produces a smooth shape
Two types of sediment
Detrital and Chemical
Three types of sedimentary environments
- Continental (Glacial Deposits)
- Transitional (the transition from continent to ocean)
- Marine (continental shelf)
List and Describe the two main lithification steps
Compaction: Particles pack more closely together
Cementation: Glues the particles together to form rocks
Metamorphism
The transformation of rocks as the result of heat, pressure, and/or fluid activity
Occurs below the melting point in the solid state
Metamorphic grade
The degree of metamorphic change a rock has undergone
